1. Field of the Invention
The present invention relates to a piezoelectric vibrating piece and a piezoelectric vibrator having the same.
2. Description of Related Art
For example, in a cellular phone and portable information terminal apparatuses, a piezoelectric vibrator using crystal and so on is used in many cases as devices used for a time source, a timing source of a control signal and so on, a reference signal source and so on. As a piezoelectric vibrator of this kind, there is known one in which a piezoelectric vibrating piece is hermetically sealed in a package where a cavity is formed.
A so-called side-arm type piezoelectric vibrating piece is known as a piezoelectric vibrating piece (for example, refer to JP-A-2008-72705 (Patent Document 1)). The side-arm type piezoelectric vibrating piece has a pair of vibrating arm portions arranged in parallel to each other at an interval in a width direction, a base portion supporting a base-end portion side of the pair of vibrating arm portions in a cantilever manner and support arm portions (side arms) extended from the base portion outside the pair of vibrating arm portions. Then, the piezoelectric vibrating piece is mounted inside a package by using the support arm portions on both sides as mount portions. Specifically, mount electrodes respectively provided on surfaces near tip ends of the support arm portions on both sides are bonded to electrode pads on a package side through a conductive bonding material such as a conductive adhesive or metal bumps. Accordingly, the piezoelectric vibrating piece can be mounted in the package as well as a voltage can be applied from outside to excitation electrodes on the vibrating arm portions.
Incidentally, a requirement for miniaturization of the piezoelectric vibrating piece is further increasing in recent years, and a bonding area between the piezoelectric vibrating piece and the conductive bonding material is reduced accordingly, the reduction of strength in mounting the piezoelectric vibrating piece is a concern. When the strength in mounting the piezoelectric vibrating piece is reduced, there is a danger that the piezoelectric vibrating piece comes off from a base substrate of the package due to an external shock and so on, and further, positional displacement of the piezoelectric vibrating piece and operation failures of electronic components may occur.